Asystolic Pause Research Articles

Cardioneuroablation for the treatment of carotid sinus syndrome

Abstract Introduction Carotid sinus syndrome (CSS), characterized by exaggerated vagal responses leading to asystolic pauses with carotid sinus massage (CSM), often necessitates pacemaker implantation. This study investigates cardioneuroablation (CNA) as an alternative management strategy for CSS. Methods Prospective study of consecutive patients referred for CNA. All patients underwent CSM, atropine test, 24-hour Holter monitoring and SF-36 quality of life questionary before the procedure and at 6 months. The objective of the study was to assess syncope free survival, grade of cardioinhibition with CSM and heart rate variation (HRV) and quality of life after the procedure. Results A total of 13 patients (84.6% male, mean age 63.8 ± 12.3 years) were included. After a median follow-up of 11.2 (10.6-16.3) months, none of the patients experienced syncope (0%) and none of the patients required pacemaker implantation. After the procedure all the patients had a negative CSM and only one patient (7.7%) had a positive CSM at 6 months (Figure 1). There was an improvement in the energy and health change items in the SF-36 quality of life questionary (Figure 2). There was a reduction in HR increase in the atropine test at 6 months (pre-CNA: 66% (52-84) vs. post-CNA 27.4% (21.9-90.9); p=0.027) and in most of the 24-hour Holter monitoring HRV parameters. Conclusions Cardioneuroablation emerges as a promising and effective alternative to pacemaker implantation in managing cardioinhibitory CSS. Further research is warranted to solidify these findings and explore the long-term effects of CNA in this scenario.Figure 1Figure 2

Endocardial ablation of ganglionated plexus for the treatment of carotid sinus syndrome.

Carotid sinus syndrome (CSS), characterized by exaggerated vagal responses leading to asystolic pauses with carotid sinus massage (CSM), often necessitates pacemaker implantation. This study investigates cardioneuroablation (CNA) as an alternative strategy for CSS. Prospective study of consecutive patients referred for CNA due to CSS. All patients underwent CSM, atropine test and 24-h Holter monitoring before the procedure and at 6 months. The primary objective was the absence of any cardioinhibitory response to CSM following CNA. Secondary objectives included the combined endpoint of syncope and presyncope-free survival, pacemaker-free survival, differences in heart rate variation (HRV), as well as differences in the pre- and postprocedure atropine tests and in the SF-36 quality-of-life questionnaire. A total of 13 consecutive patients (84.6% male, mean age 63.8 ± 12.3 years) were included. CSM revealed a symptomatic asystolic pause in all patients before CNA (7.3 [5.6-10.5] s). After the procedure, all the patients had a negative CSM, and only one patient (7.7%) had a positive CSM at 6 months. After a median follow-up of 11.2 (10.6-16.3) months, syncope or presyncope-free survival was 84.6%, and none required pacemaker implantation. There was an improvement in the energy and health change items in the SF-36 questionnaire. There was a reduction in HR increase in the atropine test at 6 months (pre-CNA: 66% [52-84] vs. post-CNA 26.0% (19.8-29.3]; p = .008) and in HRV parameters. In this proof-of-efficacy study, performed in patients affected by asystolic CSS, CNA was effective in reducing the rate of cardioinhibitory responses, suggesting a potential efficacy in also reducing syncopal recurrences. Controlled trials are warranted to corroborate clinical findings.

Endocardial ablation of ganglionated plexus for the treatment of carotid sinus syndrome

Abstract Introduction Carotid sinus syndrome (CSS), characterized by exaggerated vagal responses leading to asystolic pauses with carotid sinus massage (CSM), often necessitates pacemaker implantation. This study investigates cardioneuroablation (CNA) as an alternative management strategy for CSS. Methods Prospective study of consecutive patients referred for CNA. All patients underwent CSM, atropine test, 24-hour Holter monitoring and SF-36 quality of life questionary before the procedure and at 6 months. The objective of the study was to assess syncope free survival, grade of cardioinhibition with CSM and heart rate variation (HRV) and quality of life after the procedure. Results A total of 13 patients (84.6% male, mean age 63.8 ± 12.3 years) were included. After a median follow-up of 9.2 (8.6-14.3) months, none of the patients experienced syncope (0%) and none of the patients required pacemaker implantation. After the procedure all the patients had a negative CSM and only one patient (7.7%) had a positive CSM at 6 months (Figure 1). There was an improvement in the energy and health change items in the SF-36 quality of life questionary. There was a reduction in HR increase in the atropine test at 6 months (pre-CNA: 66% (52-84) vs. post-CNA 27.4% (21.9-90.9); p=0.027) and in most of the 24-hour Holter monitoring HRV parameters (Figure 2). Conclusions Cardioneuroablation emerges as a promising and effective alternative to pacemaker implantation in managing cardioinhibitory CSS. Further research is warranted to solidify these findings and explore the long-term effects of CNA in this scenario.Maximum RR interval with CSMHeart rate increase in the atropine tes

IMPLANTABLE LOOP RECORDER IN BRUGADA SYNDROME: INSIGHTS FROM A SINGLE–CENTER EXPERIENCE

Abstract Brugada syndrome (BrS) is characterized by a “coved” ST segment elevation of ≥2 mm in the right precordial electrocardiographic (ECG) leads, either spontaneously or drug–induced. Risk stratification in individuals with BrS remains challenging. Currently, miniaturized and remotely monitored implantable loop recorders (ILRs) are available, providing physicians with a diagnostic tool that can help guide intervention or therapy decisions for these patients. The objective of this study was to investigate the characteristics and outcomes of patients diagnosed with BrS who underwent ICM insertion during routine clinical activity. This is a retrospective single center cohort study. We screened 147 consecutive patients who were diagnosed with BrS based on the presence of spontaneous or drug–induced type 1 ECG pattern between January 2009 and May 2023. Once this comprehensive diagnostic pathway was completed, we engaged in detailed counseling with patients to discuss the potential need for ICD implantation or ILR insertion, if deemed indicated. Compared to patients who did not receive a device, those who received an ILR had a higher prevalence of suspected arrhythmic syncope (43% vs. 22%, p=0.012) and tended to be younger (median age 38 years, IQR 30–52, vs. 43 years, IQR 35–55, p=0.044) and with a higher presence of SCN5A gene mutations (17% vs. 6%). On the other hand, compared to patients who received an ICD, those with an ICM underwent programmed ventricular stimulation less frequently (40% vs. 85%, p=0.010) and, as a result, had a lower frequency of positive result of this test (0% vs. 91%, p< 0.001). During a median follow–up period of 14.7 months (IQR, 4.7–44.8), no deaths occurred among the patients with ILR. Eight individuals (19%) were diagnosed with arrhythmic findings through continuous ILR monitoring. Among these findings, three patients experienced AF (including one case of new–onset AF), two patients exhibited symptomatic asystolic pauses lasting 16 seconds and 3.6 seconds respectively, two patients had non–sustained ventricular tachycardia, and one patient had episodes of paroxysmal supraventricular tachycardia. Except for a history of AF, no significant differences were observed between patients with arrhythmic findings and those without any events. In the ICD group, the median follow–up period was 32.2 months (IQR, 23.2–95.0). During this period, no deaths occurred and no appropriate or inappropriate ICD therapies were delivered.

Implantable loop recorder in Brugada syndrome: Insights from a single-center experience

BackgroundThis study aimed to investigate the characteristics and outcomes of patients diagnosed with Brugada syndrome (BrS) who underwent implantable loop recorder (ILR) insertion during routine clinical activity. MethodsWe conducted a comprehensive screening of all consecutive patients diagnosed with BrS at our institution. We analyzed baseline clinical characteristics, arrhythmic findings, and outcomes. ResultsOut of 147 BrS patients, 42 (29 %) received an ILR, 13 (9 %) underwent implantable cardioverter-defibrillator (ICD) placement, and 92 patients (63 %) continued regular cardiological follow-up. Patients who received an ILR had a higher prevalence of suspected arrhythmic syncope (43 % vs. 22 %, p = 0.012) and tended to be younger (median age 38 years, interquartile range 30–52, vs. 43 years, 35–55, p = 0.044) with a higher presence of SCN5A gene mutations (17 % vs. 6 %, p = 0.066) compared to those who continued regular follow-up. Additionally, compared to patients with an ICD, those with an ILR had a significantly lower frequency of positive programmed ventricular stimulation (0 % vs. 91 %, p < 0.001). During a median follow-up period of 14.7 months (4.7–44.8), no deaths occurred among the patients with ILR. Eight individuals (19 %) were diagnosed with arrhythmic findings through continuous ILR monitoring, primarily atrial fibrillation, and asystolic pauses. The median time from insertion to the occurrence of these events was 8.7 months (3.6–46.4). No adverse events related to ILR were reported. ConclusionContinuous monitoring with ILR may facilitate the timely detection of non-malignant rhythm disorders in BrS patients with risk factors but without an indication for primary prevention ICD implantation.

Asystole on loop recorder in patients with unexplained syncope and negative tilt testing: age distribution and clinical predictors

BackgroundApproximately 50% of patients with unexplained syncope and negative head-up tilt test (HUTT) who have an electrocardiogram (ECG) documentation of spontaneous syncope during implantable loop recorder (ILR) show an asystolic pause at the time of the event.ObjectiveThe aim of the study was to evaluate the age distribution and clinical predictors of asystolic syncope detected by ILR in patients with unexplained syncope and negative HUTT.MethodsThis research employed a retrospective, single-center study of consecutive patients. The ILR-documented spontaneous syncope was classified according to the International Study on Syncope of Uncertain Etiology (ISSUE) classification.ResultsAmong 113 patients (54.0 ± 19.6 years; 46% male), 49 had an ECG-documented recurrence of syncope during the observation period and 28 of these later (24.8%, corresponding to 57.1% of the patients with a diagnostic event) had a diagnosis of asystolic syncope at ILR: type 1A was present in 24 (85.7%), type 1B in 1 (3.6%), and type 1C in 3 (10.7%) patients. The age distribution of asystolic syncope was bimodal, with a peak at age < 19 years and a second peak at the age of 60–79 years. At Cox multivariable analysis, syncope without prodromes (OR 3.7; p = 0.0008) and use of beta blockers (OR 3.2; p = 0.002) were independently associated to ILR-detected asystole.ConclusionsIn patients with unexplained syncope and negative HUTT, the age distribution of asystolic syncope detected by ILR is bimodal, suggesting a different mechanism responsible for asystole in both younger and older patients. The absence of prodromes and the use of beta blockers are independent predictors of ILR-detected asystole.

Efficacy and Safety of Isoprenaline during Unstable Third-Degree Atrioventricular Block.

Unstable and symptomatic complete atrioventricular block represents a potentially fatal condition that requires prompt therapy while waiting for definitive pacemaker implantation. Although transcutaneous pacing is included in acute management, it could be a difficult approach due to its painfulness and the occasional failure of mechanical capture. Drug therapy is a feasible choice, and current guidelines encompass the use of atropine, dopamine, or epinephrine. Isoprenaline has never been investigated in this setting, and no specific indication of its use has been provided despite its potentially more favorable pharmacological profile. The study population included a consecutive series of patients who presented to the emergency department because of unstable third-degree atrioventricular block and were treated with either isoprenaline or dopamine infusion while waiting for definitive pacemaker implantation. Asymptomatic patients or those with reversible causes of complete atrioventricular block were excluded. The clinical response to the drug was deemed poor if, despite achieving a full drug dose, patients remained symptomatic and/or with hemodynamic instability, ventricular rate and rhythm did not improve or worsened, including if ventricular arrhythmias or asystolic pauses and/or irrepressible nausea/vomiting occurred. Isoprenaline infusion has proved to be safe and tolerated with no arrhythmia induction or hypotensive issues. Isoprenaline has also proven to be more satisfactory in achieving an effective clinical response in 84% of patients rather than dopamine (31%, p < 0.001), reducing the need for temporary artificial pacing. Our data point out the efficacy and safety of isoprenaline infusion and its greater tolerability over dopamine in the acute management of unstable third-degree AV block while waiting for definitive pacemaker implantation.

Head-up tilt test induced asystole and recurrent syncope: a follow-up study

Abstract Introduction Head-up tilt test (HUTT) is a valuable diagnostic tool in unexplained and recurrent syncope, especially when reflex etiology is suspected. If asystole is the dominant feature of reflex syncope, permanent pacemaker therapy may be effective for reducing syncope recurrence. Purpose To investigate syncope recurrence, pacemaker implantation and death of patients with syncope and asystole induced by HUTT and carotid sinus message (CSM). Methods Retrospective analysis of consecutive patients referred for HUTT between January 2017 and December 2021 and selection of those with cardioinhibitory response, defined by syncope or pre-syncope and asystolic pause ≥3 seconds. Patients’ follow-up (FUP) was performed via a phone interview and analysis of clinical records, to assess recurrence of syncope, treatments, and death. Results A total of 44 patients were included: 30 (68,2%) were men, with a median age of 69 years (interquartile range (IQR) of 24). Asystole was experienced after CSMin 41 patients and during tilt test alone in 3 patients. Median FUP was 26 months (IQR 23). There were 19 (44,2%) patients who implanted pacemaker (PM), all with cardioinhibitory carotid sinus syndrome ( I-CSS), 57,9% men, with median age of 74 years (IQR 19) and median duration of asystole during CSMof 6,3 seconds (IQR 3,8). Of these, 5 (26,3%) implanted a unicameral PM and the remaininga bicameral PM, with AAI-DDD mode programming. Two patients had PM-related complications: infection and dislodgment of ventricular lead, both in the first 15 days after implantation. Median atrial and ventricular pacing percentage at last PM consultation was 7% (IQR 28) and 1% (IQR 4), respectively. There was a positive strong correlation between the percentage of atrial pacing at first and at last appointment (p&amp;lt;0,001, r=0,867) and a positive moderated correlation between the percentage of ventricular pacingat first and at last appointment (p=0,022, r=0,586), suggesting a similar degree of pacing along FUP-time. Only three patients (6,8%) had syncope recurrence, all men with CI-CSS, median age of 78; one patient had syncope before implantation PM, other relapsed 2-times with a PMimplanted and the third refused PMimplantation despite 5-time recurrence of symptoms. There was no association between the duration of the asystole during HUTT with implantation of PM nor syncope recurrence (p&amp;gt;0.2). Age at HUTT was significantly associated both with CI-CSS and PM implantation (p=0,001 and p=0,045, respectively). Two patients died, both of oncologic causes. Conclusion In agreement with the literature, our cohort of patients with cardioinhibitory response during HUTT and CSM experienced an overall good prognosis, with no cardiac deaths; there was very low syncope recurrence, not allowing a comparison between the groups with and without pacemaker. Age at HUTT was significantly associated both with CI-CSS and PMimplantation.

PO-02-232 CARDIONEURAL ABLATION IN THE MANAGEMENT OF LONG QT SYNDROME, TYPE 7

Vasovagal syncope is a complex interaction of neurologic and cardiovascular mechanisms resulting in cardiac inhibition by the parasympathetic nervous system via the vagus nerve and associated ganglionic plexi. Some types of tachycardia may be induced by bradycardia, LQT type 3 being the most common example. In these patients, a pacemaker is sometimes indicated to avoid the bradycardia trigger for tachycardia. Cardioneural ablation (CNA) is an emerging therapy that offers the potential of abolishing vagal-induced bradycardia. It is most commonly used to treat vasovagal syncope but it may also provide benefit to patients with bradycardia-induced tachyarrhythmias. We present a case of a patient with Long QT type 7 with vasovagal syncope who had an asystolic pause which induced a run of nonsustained VT. Cardioneural ablation was utilized to avoid bradycardia, with the intention of avoiding future triggering of VT. An 8-year-old female with a past-medical history of Andersen-Tawil Syndrome (Long QT Syndrome type 7). She had two syncopal events which suggested a vagal etiology. After loop monitor placement, she had a third syncopal event, which recorded a period of sinus bradycardia, culminating in a 6.3 second asystolic pause, followed by a 6 beat run of VT, with cycle length of 200-260 msec. Cardioneural ablation was considered as a means of avoiding future bradycardic events. Procedure was performed under general anesthesia. Electroanatomic mapping (Ensite Precision) was used to create 3D cardiac geometry. The same system, coupled with transthoracic ultrasound, was also used to guide transseptal puncture. Sinus bradycardia could be induced at baseline with vagal stimulation. Areas of fractionated signals were mapped to the high atrial septum between the right upper pulmonary vein and the fossa ovalis; and also in the roof of the coronary sinus. Patient was known to have a persistent left SVC to the coronary sinus. These areas were targeted for ablation. Post ablation, she had no bradycardia inducible with vagal stimulation. She tolerated the procedure well, without complication. CNA shows potential promise in the treatment of vasovagal syncope. However, there may be other clinical settings in which it finds utility. Conditions which might benefit include Andersen-Tawil syndrome, Long QT type 3, Brugada syndrome, and possibly Congenital Central Hypoventilation syndrome. Further investigation is needed to elucidate the safety and efficacy of CNA in these settings.

678 WIDE COMPLEX TACHYCARDIA IN A PATIENT TREATED WITH PERMANENT HIS BUNDLE PACING: A CASE REPORT

Abstract Introduction Differential diagnosis of wide complex tachycardias based only on ECG analysis remains a challenging exercise. But, when intracardiac tracings are available (i.e., pacemaker EGM), electrophysiologists may consider several tricks to make a correct diagnosis. Case Presentation A 73-years-old sporty male was admitted to our hospital for palpitations and dizziness. ECG monitoring revealed AF, typical atrial flutter and asystolic pauses following spontaneous cardioversion of atrial arrhythmias. We diagnosed sick sinus syndrome and implanted a dual-chamber pacemaker with an atrial lead in the right appendage and a stylet-directed active fixation lead in the His region, obtaining non-selective narrow paced QRS. The day after PM implantation, during a new episode of AF, two runs of regular wide-complex tachycardia (LBBB morphology, cycle length of 270 ms) occurred (Fig 1A, B). LBBB morphology, patient's history, and AF favored aberrancy, but couldn't exclude VT or preexcitation (by atrio-fascicular AP). Our diagnostic strategy consisted in adding atrial and His intracardiac electrograms registered by pacemaker to analysis of ECG traces. The device interrogation showed AV dissociation at the time of the wide complex tachyarrhythmia and a negative HV interval (Fig. 2A). These findings ruled out aberrant ventricular conduction and bundle branch reentrant tachycardia, because both these arrhythmias are characterized by HV ≥ HV in sinus rhythm. We performed incremental atrial pacing maneuver, during SR, obtaining decremental AH conduction with constant HV interval (60 ms), excluding atrio-fascicular, nodo-fascicular and nodo-ventricular AP. His bundle activity was identified just after the ventricular activation, producing a relatively short VH interval, suggesting the presence of a retrograde activation of the His bundle, therefore it was possible to hypothesize that the site of origin of the ventricular arrhythmia was within/or very close to RBB (Fig 2B, C). Just in few beats His bundle deflection was missing, probably because of recovery of functional LBBB (Fig 2D). Discussion Our final diagnosis was RBB VT. Patient was treated with Verapamil 80 mg t.i.d., with no further recurrence. This case highlights the diagnostic value of device interrogation in patients with permanent His bundle pacing, for the evaluation of wide complex tachycardias.

Influence of Age on Magnitude and Timing of Vasodepression and Cardioinhibition in Tilt-Induced Vasovagal Syncope.

Cardioinhibition may diminish with age, but the changing balance of cardioinhibition and vasodepression with age has not been quantified, leaving the mechanism of vasovagal syncope (VVS) in old ageunclear. This study sought to quantify age-related changes of vasodepression and cardioinhibition in tilt-induced VVS. We studied 163 cases of tilt-induced VVS, evoked using the Italian protocol with blood pressure, heart rate, and video-electroencephalographic monitoring. Presyncope was excluded. Cardioinhibition was defined as the heart rate decrease before syncope; asystolic pauses (≥3 seconds) were divided into early and late asystole, ie, beginning early enough to or too late to be the major cause of loss of consciousness. The log-ratio method was used to quantify contributions of cardioinhibition and vasodepression, assessed in 2 10-second periods before the onset of cardioinhibition and before syncope. With increasing age, cardioinhibition decreased, ie, heart rate decreased less and more slowly near syncope (P< 0.0001), while vasodepression increased. Asystolic pauses were less frequent in the older one-half of the group than the younger one-half (26% vs 57%; P< 0.00001), but when it did, late asystole occurred more often (58% vs 15%; P<0.001). The shift toward less cardioinhibition and more vasodepression with increased age probably reflects a physiological shift in circulatory control. The weakening of cardioinhibition with age may detract from the efficacy of pacing in older patients with VVS. Cardioinhibition-vasodepression balance should be considered in pacing decisions in older subjects with VVS.

EP News: Case Reports

Vasovagal syncope (VVS) is a relatively common event that in some patients can be disabling. Because of frequent treatment failures with historical therapies, there exists optimism with invasive denervation through radiofrequency cardioneuroablation (CNA). Thurber et al (https://doi.org/10.1016/j.hrcr.2022.04.001) shared a case of a 20-year-old woman with recurrent syncope and a family history of cardioinhibitory type VVS. She received an implantable loop recorder (ILR). Syncopal events correlated with recorded prolonged asystolic pauses.

A leadless pacemaker matched with a vasovagal syncope: how long can it last?

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Dr.Mohamed ElRefai is receiving an unrestricted grant from Boston Scientific Introduction Although a benign condition, patients suffering from frequent vasovagal syncopal episodes need treatment to improve their quality of life. ESC Guidelines consider pacing for patients &amp;gt;40 years old with documented symptomatic asystolic pauses &amp;gt;3 seconds or asymptomatic pauses &amp;gt;6 seconds. Caution is advised with use of pacing in younger patients, due to long-term complications associated with transvenous pacemakers (TV-PPM). The ESC guidelines recommend that Leadless pacemakers (LP) should be considered as an alternative to TV-PPM when there is no appropriate venous access or if the risk of device infection is high, also on a case-by-case basis using shared decision making. Studies on the use of LPs for cardioinhibitory vasovagal population specifically, concluded that the safety and efficacy of LPs are comparable with TV-PPM, demonstrating a high level of symptom improvement at follow up making them a reasonable option in these patients. In addition, observational studies demonstrated that LPs are associated with better quality of life than TV-PPM. Purpose Current practice is to implant another LP after the end of life of the old device without extracting it. There are concerns regards battery longevity specially with the paucity of data on device extraction and the number of concomitant LPs that can be implanted safely, a concern in younger patients’ population potentially requiring decades of pacing therapy. We aim to evaluate the performance of the LPs in the relatively younger vasovagal syncope patients with anticipated very low pacing dependency, with emphasis on battery longevity. Methods We conducted a retrospective analysis of the first 100 LP implanted at our tertiary referral centre for cardiac devices in the UK. Demographical data as well as devices parameters at implant and latest follow ups were obtained from the patients’ medical electronic records. We compared the performance of the LPs between patients with vasovagal syncope vs other pacing indications with emphasis on battery longevity in both groups. Results A total of 90 patients were included in our analysis after excluding 10 patients due to lack of follow-up data. 14 patients (15.6%) had vasovagal syncope as indication for pacing and 76 patients (84.4%) had other indications. Mean ages were 34±13 years and 62±20 years for the vasovagal and the other group, respectively. There were no complications in the vasovagal group. Pacing % at the last follow up was 1±1 in the vasovagal group and 37±43 for the other group. There was a significant difference in the estimated total battery life between both groups, 15.22±0.35 and 13.65±2.97 years in the vasovagal and the other group respectively. Conclusion LPs provide a safe and a reliable treatment for young patients with vasovagal syncope with promising battery performance at the short/intermediate term. Further longer-term follow up data is needed to identify the true battery potential in this patient cohort.

P376 INTRACAVITARY ABLATION OF PARASYMPATHETIC ATRIAL GANGLIONATED PLEXUS, A NEW APPROACH FOR SINUS BRADYCARDIA IN YOUNG PATIENTS

Abstract Sinus bradycardia might be a severe clinical problem, if symptomatic pacemaker implantation is needed. In younger patients this will lead to several battery changes, higher infectious risk and psychological issues. When sinus bradycardia seems related to vagal hypertone, intracavitary ablation of atrial ganglionated plexus has recently been proposed as an alternative to pacemaker implantation in symptomatic younger patients. A 44–year–old patient was admitted to the emergency department for lipothymia and fatigue. The ECG showed marked sinus bradycardia with a heart rate of 35 bpm and continuous ECG monitoring revealed episodes of Mobitz I second degree AV block and 2:1 AV block. The transthoracic echocardiography was normal. In order to reduce the effect of vagal hypertone on the heart, catheter ablation of parasympathetic atrial ganglionated plexus was performed. In the right atrium the electrophysiological study showed fragmented potentials near caval vein openings and coronary sinus osthium, while in the left atrium these were found in the posterior wall close to the pulmonary veins and near the left part of coronary sinus. Catheter stimulation of these zones determined asystolic pauses and induction of atrial fibrillation with spontaneous resolution. Catheter radio–frequency ablation was performed, at the end of the procedure increase of heart rate at 70 bpm was observed and atrial fibrillation was no more inducible during pacing. Atrioventricular Wenckebach point recorded before the procedure was 730 ms and it passed to 430 ms. At continuous ECG monitoring the heart rate remained higher than 65 bpm all over the hospitalization, without any other meaningful arrhythmias. Ablation of parasympathetic atrial ganglionated plexus is still an experimental technique but it is proving to be very interesting and promising. In the case we described the patient took a real advantage from the procedure that was measurable both with the improve of heart rate and reduction of Wenckebach point. During the procedure we associated the site of fragmented potentials with the position of each plexus; stimulation of these sites evocated a strong vagal response, confirming that fragmented potentials can be used to localize the plexus. Some authors affirmed that ablation only on right atrium might be sufficient; however, we preferred to ablate in both atria in order to make the procedure more effective. More studies are needed to identify the correct site.

PO-699-02 CARDIONEUROABLATION: SELECTIVE TREATMENT OPTION FOR CARDIOINHIBITORY SYNCOPE

Reflex cardioinhibitory syncope is common, and until recently, permanent pacemaker implantation was the only treatment option - and even then, an option with only modest efficacy in preventing recurrent syncope. Radiofrequency (RF) catheter ablation of epicardial ganglionated plexi (GP) is increasingly being explored as a therapeutic option. To assess the safety and efficacy of a consecutive group of patients (with a substantial rate of implantable monitoring follow-up) treated by cardio-neuroablation (CNA) in a single center. CNA is considered in pts after a positive atropine test. Under general anesthesia, electroanatomical LA / RA maps are created (CARTO, NavX). RF energy is applied to the GP predilection sites in both atria until the vagal response to high-frequency (HF) stimulation of the vagal nerve (at jugular vein level) is completely eliminated. A total of 31 patients (age 40.0 ± 8.5 yrs; 18 M / 13 W; BMI 26.6 ±4.9; normal LVEF and LA size) with cardioinhibitory syncope were treated with CNA. Three patients had prior pacemakers including two leadless pacers, and 15 pts (50%) had implantable loop recorders (ILRs). All patients had a positive atropine test pre-CNA. The indications for CNA were: syncope based on sinus bradycardia/arrest in 18 patient s, high degree AV block in 12 patients, and a combination of both in 1 patient. The average longest asystolic pause was 5 sec (range 3 - 40). The average number of syncopal events was 4 per patient (range 0-20). The median procedural time was 156 ± 46.9 min; the mean fluoroscopy time was 8.2 ± 4.4 min. Using a total of 28 ± 15 RF applications (total ablation time was 1736 ± 839 sec), the endpoint of abolishing any vagal response to HF stimulation was achieved in 100% of patients. There was one serious complication - a femoral artery pseudoaneurysm requiring surgery. During clinical follow-up (mean 10 months), including ILR interrogation, only 1 in 30 (3.3%) pts had recurrent syncope or significant bradycardia were. No patient required permanent pacing after CNA. Our observational study demonstrated that GP ablation is a safe procedure with an efficacy exceeding 95%. CNA should be evaluated in a randomized clinical trial.

Micturition syncope with asystole in a paediatric patient.

Syncope occurs frequently in children, and the differential includes situational syncope, specifically micturition syncope. We report the youngest child to our knowledge to have micturition syncope associated with a prolonged asystolic pause. He underwent a neurological and cardiovascular evaluation without additional findings. Behavioural modifications were instituted with no recurrent syncope.

Cardiac pacing in severe recurrent reflex syncope and tilt-induced asystole

AimThe benefit of cardiac pacing in patients with severe recurrent reflex syncope and asystole induced by tilt testing has not been established. The usefulness of tilt-table test to select candidates for cardiac pacing is controversial.Methods and resultsWe randomly assigned patients aged 40 years or older who had at least two episodes of unpredictable severe reflex syncope during the last year and a tilt-induced syncope with an asystolic pause longer than 3 s, to receive either an active (pacing ON; 63 patients) or an inactive (pacing OFF; 64 patients) dual-chamber pacemaker with closed loop stimulation (CLS). The primary endpoint was the time to first recurrence of syncope. Patients and independent outcome assessors were blinded to the assigned treatment. After a median follow-up of 11.2 months, syncope occurred in significantly fewer patients in the pacing group than in the control group [10 (16%) vs. 34 (53%); hazard ratio, 0.23; P = 0.00005]. The estimated syncope recurrence rate at 1 year was 19% (pacing) and 53% (control) and at 2 years, 22% (pacing) and 68% (control). A combined endpoint of syncope or presyncope occurred in significantly fewer patients in the pacing group [23 (37%) vs. 40 (63%); hazard ratio, 0.44; P = 0.002]. Minor device-related adverse events were reported in five patients (4%).ConclusionIn patients aged 40 years or older, affected by severe recurrent reflex syncope and tilt-induced asystole, dual-chamber pacemaker with CLS is highly effective in reducing the recurrences of syncope. Our findings support the inclusion of tilt testing as a useful method to select candidates for cardiac pacing.Study registrationClinicalTrials.gov identifier NCT02324920, Eudamed number CIV-05-013546.

Abstract 15291: ‘Heart Rate Deficit’ From Dysautonomia in a Bariatric Surgery Patient - An Unusual Cause of Recurrent Syncope

Background: Patients undergoing bariatric surgery are prone to develop symptomatic dysautonomia but the mechanisms remain unclear. Methods: N/A Results: A 61-year-old female with hyperlipidemia, fibromyalgia, morbid obesity status post gastric sleeve 2 years prior, was transferred to our institution after an unremarkable initial cardiac workup for recurrent syncope and bradycardia. Patient had significant weight loss (180 lbs) post-surgery over this 2-year period but began noticing increasing fatigue, and exercise intolerance in the last four months preceding recent syncopal episodes. Syncopal spells happened while trying to lift her head &gt;60 degrees/sit up from a recumbent position. Baseline heart rate (HR) was 36-42 bpm (Figure lower Panel) while it was 75-90 bpm immediately following bariatric surgery (Figure upper panel). Blood pressure was normal. During witnessed syncopal episodes, HR remained in the 35-40 bpm range with no asystolic pauses and normal blood pressure. Video EEG showed loss of brain electrical activity during syncope; no seizure activity was noted. Progressive decline in HR and baseline bradycardia was suspected as the cause and she underwent permanent pacemaker implantation, which resulted in complete resolution of symptoms and no recurrence of syncope at 6-mo follow-up. Conclusion: We describe a unique case where marked decline in resting HR occurred in association with significant weight loss following bariatric surgery. This ‘HR deficit’ and resting bradycardia, likely due to dysautonomia, resulted in recurrent syncope without asystole or vasodepression, and completely resolved with permanent pacemaker implantation.

ELectrophysiological mechanisms underlying the Inhibitory CArdiac syncope without asystolic significant pause: Therapeutic and prognostic implications. The ELICA randomized trial.

Background:The aim of this study was to investigate syncope recurrence in patients with a 2A cardioinhibitory response to the head up tilt testing (HUT).Methods:In this study, we enrolled 72 consecutive patients affected by syncope with cardioinhibitory response without asystolic significant pause to HUT (2A type). In these patients, we randomly performed electrophysiological study (ES). In case of sino-atrial node, atrio-ventricular node dysfunction, and sustained arrhythmias induction, the ES resulted positive. ES was positive in 9 patients (group A), then treated by catheter ablation, and/or by devices implants. Otherwise, ES resulted negative (group B), and these patients did not receive an interventional treatment. However, after ES, we evaluated syncope recurrence during 360 days follow-up.Results:There was a lower statistical significant syncope recurrence at follow-up, comparing group A to group B of patients [n of events 9 (40.9%) vs 8 (57.1%), P < .05]. At multivariate analysis, ES result was the only factor predicting syncope recurrence at follow-up (hazard ratio = 27.63, 95% confidence interval = 1.02–54.24, P < .005).Conclusion:The positivity to ES study, and successful interventional therapies may reduce the burden of syncope recurrence at 360 days follow-up in 2A HUT subjects.Clinical trial number: NCT02861274.

The benefit of pacemaker therapy in patients with neurally mediated syncope and documented asystole: a meta-analysis of implantable loop recorder studies

Although the efficacy of cardiac pacing in patients with neurally mediated syncope (NMS) and documented asystole is established, a more robust point estimate of the benefit, which is not possible with any individual study, is lacking. We undertook a meta-analysis of individual participant data from four studies that reported follow-up data on syncope recurrence with cardiac pacing in patients with NMS who had had an electrocardiographic (ECG) documentation of an asystolic event by means of implantable loop recorder (ILR). Of a total of 1046 patients, who had ILR implanted, 383 (36.6%) patients had an ECG documentation of a diagnostic event during mean follow-up of 13 ± 10 months. Of these, 201 (52%) patients, corresponding to 19.2% of the total ILRs, had an asystolic event of 12.8 ± 11.0 s duration documented and met the criteria for pacemaker therapy. Follow-up was available in 121 (60%) of those patients with asystolic events. Syncope recurred after pacing in 18 (14.9%) patients with an actuarial rate of 13% [95% confidence interval (CI) ±6] at 1 year, 21% (95%CI ±10) at 2 years, and 24% (95%CI ±11) at 3 years. On multivariable Cox regression analysis, positive tilt test response was the only significant predictor of syncope recurrence with a hazard ratio (95% CI) of 4.3 (1.4-13). On the contrary, type of asystolic event (sinus arrest or atrioventricular block), prodrome, cardiac abnormalities, number and duration of history of syncope, age, and gender were not predictors of recurrence of syncope. A long asystolic pause, suitable for pacemaker therapy, was found in one of five patients with ILR. After pacemaker implantation, most of these patients remained free of syncope recurrence for up to 3 years. The benefit of pacemaker was greater in patients with negative tilt test.